Pull-out behavior of oxidized copper leadframes from epoxy molding compounds

Abstract Because of their high electrical and thermal conductivities, copper-based alloys have recently experienced increased demand for use in leadframes. There is, however, a concern about the adhesion of copper-based leadframes to epoxy molding compounds (EMCs), as poor adhesion has been partly responsible for delamination and cracking in plastic packages during reflow soldering. In this study, copper-based leadframe sheets were oxidized in a brown-oxide and/or a black-oxide forming solution to improve the adhesion strength between the copper and the epoxy resin. The effects of the formation of oxides on the adhesion strength of leadframe to EMC were studied using pull-out specimens. After the pull-out tests, fracture surfaces were analyzed by various techniques to find out the failure paths. Each oxidation treatment showed different adhesion behavior and failure paths according to oxidation time. Keywords: